(a) Field of the Invention
The present invention relates to a panel module for an LCD (liquid crystal display) module and, more particularly, to a panel module including an LCD panel and a plurality of circuit boards attached thereto and used for an LCD module or an LCD device including the panel module and a backlight unit attached thereto.
(b) Description of the Related Art
LCD devices are increasingly used as flat-panel display units in computer systems as well as mobile data terminals and television sets, replacing conventional CRTs which have been used for a long time. FIG. 7 shows a partial top plan view of a conventional LCD device 50 having a panel module, described in Patent Publication JP-A-11-38430, including an LCD panel and a plurality of circuit boards, such as tape carrier packages (TCPs) 53 and 54 and terminal boards 55, attached thereto. The LCD panel includes a rear TFT substrate 51, a front counter substrate 52 having a somewhat smaller area and opposing the TFT substrate 51, and an LC layer (not specifically shown) sandwiched therebetween.
The terminal board 55 is disposed in the vicinity of the peripheral area of the TFT substrate 51, wherein the terminal board 55 and a plurality of signal line driver ICs 57 for driving the signal lines extending in the column direction of the TFT substrate 51 are electrically connected together via a flexible printed circuit board 54. The terminal board 55 and a plurality of scanning line driver ICs 58 for driving scanning lines extending in the row direction of the TFT substrate 51 are also connected together via a flexible printed circuit board 53 and a connector 56 disposed in the peripheral area of the TFT substrate 51.
More specifically, by using the flexible printed circuit boards 53 and 54, the signal line driver ICs 57 and 58 are connected to the external circuit (not shown) via the terminal board 55. In addition, part of the lines on the TFT substrate 51 is also connected to a backlight unit disposed at the rear side of the LCD panel. This type of LCD device is referred to as flat-type or stacked board structure, due to the TFT substrate 51 and the terminal board 55 being disposed within the same plane.
FIG. 8 shows another type of panel module in an LCD device, described in JP-A-2000-284311, wherein a TFT substrate 61 and a control circuit substrate 62 having a function of the terminal board are connected together via a plurality of signal line driver TCPs 64 each mounting thereon a signal line driver IC 63. During fabricating the LCD device, TCPs 64 are bent onto the rear side of the LCD panel after connecting the TCPs 64 to the TFT substrate 61 and mounting the backlight unit on the rear side of the LCD panel, thereby allowing the control circuit board 62 to be disposed on the rear side of the backlight unit of the LCD device.
Another circuit board 67 mounting thereon scanning line driver ICs 68 is connected to the control circuit board 62 via a connector 66 and a flexible cable 65 attached to the control circuit board 62. The panel module 60 of FIG. 8 has a reduced planar area by disposing the control circuit board 62 on the rear side of the backlight unit while using U-shaped circuit boards.
Another LCD device including a panel module having L-shaped circuit boards is also known wherein the control circuit boards extend normal to the screen of the LCD panel.
Development of fabrication techniques of the LCD devices allows modules of different parts to be more frequently used in the LCD device, in view that these parts of the LCD device are generally fabricated by different manufactures or different divisions in the manufacture and thus should be efficiently carried between these manufactures or divisions. Examples of these modules include an LCD panel wherein a TFT substrate and a counter substrate mounting thereon color filters are assembled with an LC layer sandwiched therebetween, a panel module wherein the TFT substrate in the LCD panel is attached with a plurality of circuit boards such as driver TCPs and terminal boards, a backlight unit or backlight module wherein a plurality of lamps and a plurality of optical sheets are assembled within a chassis, and an LCD module wherein the panel module is attached with the backlight unit. It is to be noted that the panel modules are manufactured to be used for respective types of LCD devices and dedicated to respective LCD devices each having a stacked, L-shaped or U-shaped structure.
As will be understood from the above descriptions, the panel modules described in those patent publications are dedicated to respective types of the LCD devices, and accordingly, the panel modules and LCD modules are manufactured as dedicated modules, which are dedicated to respective types of the LCD devices.
Although the LCD panels and panel modules are manufactured for the respective types of the LCD modules, manufacture of the dedicated LCD panels and dedicated panel modules for respective types of the LCD devices raises the costs for the LCD panels and panel modules. Thus, common panel modules and common LCD modules are desired which are adapted to all the types of the LCD devices having respective arrangements of the circuit boards.
In addition, some LCD device manufacturers receive the panel modules from the manufacturer of the panel modules, assemble the LCD devices by attaching thereto the backlight units and sell the resultant LCD devices as their own products. In such a case, the manufacturer of the panel modules must prepare different panel modules adapted to the respective types of the LCD devices requested by the LCD device manufactures, which restricts the design choice in the manufacturer of the panel modules.
In particular, for disassembling the backlight unit from the panel module in the LCD device having the panel module of FIG. 8, it is generally necessary to straighten the bends of the TCPs and disconnect the interconnect lines between the control circuit board and the scanning line driver ICs before disassembling the backlight unit. Thus, if the backlight unit is to be disassembled from the panel module during a product test of the LCD module or LCD device, the function of the driver ICs cannot be examined while observing the image display On the LCD device.